[ttml2] Pull Request: Add special semantics for tta:speak (#1013).

skynavga has just submitted a new pull request for https://github.com/w3c/ttml2:

== Add special semantics for tta:speak (#1013). ==
Closes #1013.

See https://github.com/w3c/ttml2/pull/1167

Received on Monday, 23 September 2019 00:40:18 UTC